Quantifying thiol–gold interactions towards the efficient strength control

• Published in: Nature communications Vol. 5; no. 1; p. 4348
• Main Authors: Xue, Yurui, Li, Xun, Li, Hongbin, Zhang, Wenke
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 07.07.2014; Nature Publishing Group
• Subjects: 140/133; 140/146; 639/301/923/966; 639/925/357/354; Environmental changes; Gold; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms5348

The strength of the thiol–gold interactions provides the basis to fabricate robust self-assembled monolayers for diverse applications. Investigation on the stability of thiol–gold interactions has thus become a hot topic. Here we use atomic force microscopy to quantify the stability of individual thiol–gold contacts formed both by isolated single thiols and in self-assembled monolayers on gold surface. Our results show that the oxidized gold surface can enhance greatly the stability of gold–thiol contacts. In addition, the shift of binding modes from a coordinate bond to a covalent bond with the change in environmental pH and interaction time has been observed experimentally. Furthermore, isolated thiol–gold contact is found to be more stable than that in self-assembled monolayers. Our findings revealed mechanisms to control the strength of thiol–gold contacts and will help guide the design of thiol–gold contacts for a variety of practical applications. The thiol–gold interaction is a fundamental one for the functionalization of nanoparticles and surfaces. Here, the authors use AFM to study individual thiol–gold contacts, showing that oxidized gold surfaces enhance the stability, in addition to monitoring shifts from coordinated to covalent bonding.